Mechanisms Of Drug-induced Toxicities

药物引起的毒性机制

• 批准号: 7154342
• 负责人: Lance R Pohl
• 金额: --
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7154342
• 关键词: Kupffer' s cell; acetaminophen; acetylcysteine; cytokine; cytoprotection; cytotoxicity; drug adverse effect; genetically modified animals; heat shock proteins; hepatotoxin; inflammation; interleukin 13; laboratory mouse; liver toxic disorder; microarray technology; pharmacokinetics

We have continued our studies of the molecular basis of drug-induced liver disease (DILD), which is a rare but often life-threatening toxicity. It is the major cause of acute liver failure and a principal reason drugs are withdrawn from clinical use. We have hypothesized that the idiosyncratic nature of this disease is due in part to a deficiency in hepatoprotective factors. This idea has been explored in the following ways this year: 1. Last year we reported that endogenous IL-13 can protect mice from acetaminophen-induced liver disease (AILD), which is a leading cause of drug-induced liver failure. This year with the use of IL-13 knockout mice and multiplex protein chips we have discovered that IL-13 deficiency leads to the over-expression of several proinflammatory cytokines and chemokines, which may have a role in determining the susceptibility of mice and possibly humans to liver disease caused by acetaminophen and other drugs. 2. Last year we reported that one of the ways the antidote N-acetyl-L-cysteine (NAC) may protect mice and possibly humans from AILD is by up-regulating several potential hepatoprotectic factors including heat shock proteins, acute phase proteins, and cell cycle regulation genes. This year we have found that one of the acute phase proteins induced by NAC in the liver is lipocalin 2. We are currently determining whether deficiency in this acute phase protein, produced by administering neutralizing antibodies to wild type mice or by the use of lipocalin 2 knockouts, makes mice more susceptible to AILD. 3. Last year we investigated the multiplicity of hepatoprotectant factors in DILD by comparing the liver proteomes of resistant (SJL) and susceptible (C57Bl/6) strains of mice to AILD with the use of isotope-coded affinity tag (ICAT) mass spectrometry. The results revealed that SJL mice had higher levels of several proteins that could potentially protect the liver from injury. This year we have explored the polygenicity of regulatory factors by comparing hepatic mRNA expression profiles of these two strains of mice with that of SJLxB6-F1 hybrid mice, which were found to be of intermediate susceptibility to AILD. Global hepatic gene expression profiling over a 24 h period following APAP treatment revealed a unique elevated pattern in the mRNA expression of several cytoprotective genes in resistant SJL mice compared to susceptible B6 mice, while SJLxB6-F1 mice had intermediate mRNA expression levels of these genes. One of these genes encoded for heat shock protein (HSP) 70 whose relative protein expression among the three strains of mice was found to parallel that of their mRNA levels, suggesting that this protein had a protective role against AILD. However, there was no difference in the susceptibility of HSP70 knockout mice to AILD compared to wild-type mice. There were also a number of pro-inflammatory genes, such as osteopontin, with elevated mRNA expression levels in the B6 mice compared to the SJL mice, and with intermediate levels in the SJLxB6-F1 mice, suggesting that they may play a role in exacerbating liver injury after APAP treatment. In support of this idea, osteopontin knockout mice were found to be more resistant to AILD than wild-type mice. Additionally, the results from both the proteomic and genomic studies were compared and found to be complementary to each other and not simply overlapping. 4. Current evidence indicates that DILD is often caused by an allergic response (drug-induced allergic hepatitis, DIAH) induced by hepatic drug-protein adducts. The low incidence of DIAH and inability to reproduce it in animals suggests that tolerogenic mechanisms may prevent DIAH from occurring in most people and animals. In this regard, last year we discovered that hepatotoxic doses of APAP were associated with marked lymphocytolysis in the thymus, spleen, and hepatic lymph nodes of mice. This year we have found that CD4 and CD8 single positive T cells as well CD4CD8 double positive T cells and B cells are diminished by this process, resulting in the inhibition of the adaptive immune system. Moreover, the degree of lymphocytolysis correlated with serum corticosterone levels, suggesting a role of this stress hormone in the mechanism of lymphocytolysis. Similar processes may occur in humans and help explain the relatively low incidence of DIAH.

我们继续研究药物性肝病（DILD）的分子基础，这是一种罕见但通常危及生命的毒性。它是急性肝衰竭的主要原因，也是药物退出临床使用的主要原因。我们推测，这种疾病的特异质性质部分是由于缺乏肝保护因子。这一想法在今年通过以下方式进行了探索： 1.去年，我们报道了内源性IL-13可以保护小鼠免受对乙酰氨基酚诱导的肝病（AILD），这是药物诱导的肝功能衰竭的主要原因。今年，通过使用IL-13敲除小鼠和多重蛋白芯片，我们发现IL-13缺乏导致几种促炎细胞因子和趋化因子的过度表达，这可能在决定小鼠和可能的人类对对乙酰氨基酚和其他药物引起的肝脏疾病的易感性方面发挥作用。 2.去年，我们报道了解毒剂N-乙酰-L-半胱氨酸（NAC）保护小鼠和可能的人类免受AILD的方式之一是通过上调几种潜在的肝保护因子，包括热休克蛋白，急性期蛋白和细胞周期调控基因。今年，我们发现NAC在肝脏中诱导的急性期蛋白之一是脂质运载蛋白2。我们目前正在确定是否缺乏这种急性期蛋白，通过给予野生型小鼠中和抗体或通过使用脂质运载蛋白2敲除产生，使小鼠更容易患上AILD。 3.去年，我们通过使用同位素编码的亲和标签（ICAT）质谱法比较抗（SJL）和敏感（C57 B1/6）小鼠品系对AILD的肝脏蛋白质组，研究了DILD中保肝因子的多样性。结果显示，SJL小鼠具有更高水平的几种蛋白质，这些蛋白质可能会保护肝脏免受损伤。今年，我们通过比较这两个品系小鼠与SJLxB 6-F1杂交小鼠的肝脏mRNA表达谱，探索了调节因子的多源性，发现SJLxB 6-F1杂交小鼠对AILD具有中等易感性。APAP治疗后24小时内的整体肝脏基因表达谱显示，与易感B6小鼠相比，耐药SJL小鼠中几种细胞保护基因的mRNA表达呈独特的升高模式，而SJLxB 6-F1小鼠中这些基因的mRNA表达水平居中。其中一个基因编码的热休克蛋白（HSP）70的相对蛋白质表达的三个品系的小鼠被发现平行，其mRNA水平，这表明该蛋白质对AILD的保护作用。然而，与野生型小鼠相比，HSP 70敲除小鼠对AILD的易感性没有差异。还有一些促炎基因，如骨桥蛋白，与SJL小鼠相比，B6小鼠的mRNA表达水平升高，SJLxB 6-F1小鼠的mRNA表达水平居中，这表明它们可能在APAP治疗后加重肝损伤中发挥作用。为了支持这一观点，发现骨桥蛋白敲除小鼠比野生型小鼠对AILD更具抵抗力。此外，比较了蛋白质组学和基因组学研究的结果，发现它们是互补的，而不是简单的重叠。 4.目前的证据表明，DILD通常是由肝脏药物-蛋白加合物诱导的过敏反应（药物诱导的过敏性肝炎，DIAH）引起的。DIAH的低发病率和不能在动物中复制它表明，致耐受性机制可能会阻止DIAH在大多数人和动物中发生。在这方面，去年我们发现APAP的肝毒性剂量与小鼠胸腺、脾脏和肝淋巴结中显著的淋巴细胞溶解有关。今年我们发现，CD 4和CD 8单阳性T细胞以及CD 4-CD 8双阳性T细胞和B细胞通过该过程减少，导致适应性免疫系统的抑制。此外，淋巴细胞溶解的程度与血清皮质酮水平相关，这表明这种应激激素在淋巴细胞溶解机制中的作用。类似的过程也可能发生在人类身上，这有助于解释DIAH发病率相对较低的原因。